The present invention relates generally to pupilometry systems and, more particularly, to pupilometry systems having a pupil irregularity detection, pupil tracking, and pupil response detection capability, as well as glaucoma screening capability, corneal topography measurement capability, intracranial pressure detection capability, and ocular aberration measurement capability. In one particularly innovative aspect, the present invention relates to hand-held pupilometry systems having a pupil irregularity detection capability, to methods and processing sequences used within such systems, and to methods of using such systems.
In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer and medical database for correlating actual or derived pupilary image analysis data with stored medical data to formulate medical diagnoses, and to methods of implementing and utilizing such a diagnostics system.
In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer which can be used to screen for Glaucoma, and for methods of implementing and utilizing such a diagnostics system.
In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer for detecting elevated intracranial pressure, and for methods of implementing and utilizing such a diagnostics system.
In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer for assessing the level of brain function, and for methods of implementing and utilizing""such a diagnostics system.
In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer for testing the functional integrity of afferent peripheral and cranial pathways as well as testing efferent cranial nerve involvement in patients with afferent pupilary defects, and for methods of implementing and utilizing such a diagnostics system.
In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer for testing the functional integrity of auditory pathways, and for methods of implementing and utilizing such a diagnostics system.
Systems for monitoring pupil size and pupil responsiveness characteristics are well known in the art and are generally referred to as pupilometry systems or, simply, pupilometers. One early pupilometer is described in U.S. Pat. No. 3,533,683, which issued to Stark et al. on Oct. 13, 1970 and is entitled xe2x80x9cDynamic Pupilometers Using Television Camera Systemxe2x80x9d (incorporated herein by reference). The Stark et al. system employed a television camera system, a digital computer system, an infrared light source, and a visual light stimulator for determining the instantaneous size of a pupil as an eye (or neurologic pupilary control system) of a patient was exposed to various stimuli. Like the early Stark et al. system, conventional pupilometers measure, for example, the diameter of a pupil before and after the pupil is exposed to a light stimulus pulse and also measure the rates at which the pupil may constrict and dilate in response to the initiation and termination of the light stimulus pulse. Pupilometers may comprise hand-held units or, alternatively, may comprise desk or table-mounted, stand-alone units. Pupilometers also generally include some mechanism for ensuring that an imager within the pupilometer is properly positioned in relation to a pupil to be imaged. For example, U.S. Pat. No. 5,646,709 (incorporated herein by reference), issued to Elbert P. Carter, describes an electronic centering system for ensuring that a pupilometer is properly positioned in relation to a pupil to be imaged. Similarly, U.S. Pat. No. 5,187,506 (incorporated herein by reference), issued to Elbert P. Carter, describes an eye orbit housing for ensuring proper positioning between a pupilometer and an eye of a subject prior to the initiation of a pupilary scanning procedure.
Those skilled in the art will appreciate, however, that for a pupilometer to have maximum utility maximum flexibility should be provided for positioning the imager. For example, in the case of a hand-held system few, if any, restrictions should be placed upon the orientation of the imager prior to enabling an imaging function. The reason for this is that medical personnel at, for example, an accident site may have difficulty in positioning an imager in a prescribed position for acquiring pupilary response data. Thus, it is believed that, for hand-held units in particular, a need exists within the pupilometer field for improved data acquisition and processing systems and methods, as such systems and methods may substantially reduce system dependence on imager orientation and may allow pupilometers to become more user friendly.
Similarly, those skilled in the art will appreciate that a need exists for pupilometers that are capable of evaluating more than a mere pupilary response to light stimulus pulses. For example, it is believed that a substantial need exists for a pupilometer that is capable not only of measuring changes in pupilary diameter in response to one or more light stimulus pulses, but also of evaluating pupil shape and/or segmental responses to a visual stimulus. Stated somewhat differently, it is believed that a substantial need exists for a pupilometer having a pupilary shape irregularity or non-uniformity detection capability.
Finally, it is believed that a substantial need exists for pupilometer-based diagnostics systems, as such systems may provide medical practitioners with a cost effective, non-invasive means for gathering and assessing numerous physiologic parameters.
For example, the present invention can be used to screen for Glaucoma, which is the second leading cause of blindness in the world. Visual field perimetry is presently used for diagnosing Glaucoma. In visual field perimetry, a white background and multiple green flicker sources are used. The green sources are randomly turned on for approximately one second durations and the subject patient is asked to press a button if he/she sees a green light. The procedure is repeated until the entire visual field is mapped for each eye. Loss of visual field sensitivity is indicative of Glaucoma.
The current standard of care for Glaucoma detection, however, suffers form inaccuracy and human/patient error. The current standard of care relies on the patient to respond to his or her visual detection of green light by pressing a button. The patient has a limited window of time in which to respond to the green light. Thus, if the patient is not concentrating or responds too quickly or too slowly, the perimetry device will not register the patient""s response, and the accuracy of the diagnosis is compromised. Furthermore, current perimetry devices are large machines that are immobile. They are for use in doctors"" offices only. Thus, a need exists for improved systems and methods for Glaucoma detection, and the present invention meets these needs and solves the problems associated with standard techniques.
Another area of diagnostic need relates to assessing the level of brain function to diagnose disorders such as autism, age-related disorders, and drug impairment or intoxication. Neurological exams today do not typically include pupilometry beyond the use of a pin-light. Currently, expensive and/or time-consuming tests are required to diagnose impairment of brain function. And, the pin-light test is subjective, non-quantifiable, and inaccurate. The present invention solves these by providing a method and system to closely track the pupil while presenting the eye with a moving visual stimuli to determine the level of coordination. The present invention is capable of quantifying tracking errors, which might occur in the course of a neurological exam, and reduces the subjectivity and increases the repeatability of exams to assess brain function.
Another area of diagnostic need is diagnosis of neurological disease or trauma. Dermatome mapping of patients is commonly done with a pin-prick to determine the level of dorsal root or spinal cord injury. This test, however, is subjective and usually requires cognitive response from a patient. There exists a need for noninvasive diagnosis of neural damage or trauma. The present invention fills that need by providing a means of quantitatively measuring pupilary response to noxious stimulation. Furthermore, this invention is useful in diagnosing dorsal root and spinal cord injuries in unconscious patients with no cognitive response capabilities. It is further useful in diagnosing and monitoring the progression of demyelinating diseases such as multiple sclerosis, which affects conduction velocity through nerve fibers. In addition, testing the level of epidural anesthetic block may be accomplished using pupilometry with this automated stimulus control.
Finally, an area of diagnostic need relates to testing the functional integrity of auditory pathways, i.e., hearing screening. Particularly with infants, hearing has been subjectively screened using stimuli such as in a clap test while observing the startle response. Other tests, such as EEG-type brain stem audible evoked potential (AEP) monitoring systems have been used, but require attachment of electrodes to the scalp and are cumbersome to use. Middle ear tone-feedback monitoring is also used, but is not capable of measuring latency information. The present invention solves these and other problems associated with the prior art by providing hearing screening using objective pupilometer-based testing systems and methods. The pupilometer-based systems are not cumbersome, are easy to use and provide latency information for diagnosing and monitoring the progression of demyelinating diseases.
In one particularly innovative aspect, the present invention is directed toward a pupilometer having a pupil shape irregularity detection capability. For example, a pupilometer in accordance with the present invention may comprise an imaging sensor for generating signals representative of a pupil of an eye, a data processor coupled to the imaging sensor, and a program executable by the data processor for enabling the data processor to process signals received from the imaging sensor and to thereby identify one or more regions of non-uniformity or irregularity within an image of a perimeter of the imaged pupil.
In one presently preferred embodiment, the one or more regions of pupilary non-uniformity or irregularity are identified by identifying a center point of a pupil and determining a plurality of radii representing distances from the center point to the perimeter of the pupil along a respective plurality of angles in a R,xcex8 coordinate system.
In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer and medical database for correlating actual or derived pupilary image analysis data with stored medical data to formulate medical diagnoses, and to methods of implementing and utilizing such a diagnostics system.
In still other innovative aspects, the present invention is directed to improved thresholding and image data processing algorithms for use within a pupilometer. For example, a pupilometer in accordance with the present invention may utilize a plurality of row and column histogram data sets in an iterative fashion to identify a preferred threshold value for locating the pupil of an eye within an image data frame.
A pupilometer in accordance with the present invention may also process image frame data to determine a shape and/or diameter of the sclera/iris border of an eye and, thereafter, use the determined shape or diameter to evaluate an orientation of the eye of the patient and/or to correlate measured units with defined units of measurement.
When provided with an additional armature supporting, for example, a visible light emitting diode (LED), a pupilometer in accordance with the present invention may be used to measure afferent or consensual pupilary responses to visual stimulus pulses. In such embodiments, a visual stimulus is applied to an eye under examination, and the response of the monitored pupil is recorded and evaluated. Then, as the monitored pupil is allowed to dilate, a stimulus pulse is applied to the other eye of the patient, to see whether or not the monitored pupil again constricts. Following the second stimulus pulse, the monitored pupil is allowed again to dilate, and a final visual stimulus is applied to the eye under examination. During the final stimulus pulse, the constrictive response of the monitored pupil (or lack thereof) is again measured. By measuring the response of the monitored pupil to each stimulus pulse, it is possible to detect retinal impairment in each eye of the patient.
In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer, which can be used to screen for Glaucoma, and for methods of implementing and utilizing such a diagnostics system. This system comprises a pupilometer comprising an imaging sensor for generating signals representative of a pupil of an eye, a data processor, and a program executable by said data processor for enabling said data processor to process signals received from said imaging sensor and to thereby identify the pupil""s dynamic response to a light stimulus. The program is further capable of storing the pupil""s response data and comparing it to a database of normal measurements to determine if the test responses fall out of range. Alternatively, the program can transmit the data to a microprocessor or peripheral computer, which has stored therein a database of normal measurements, and wherein the microprocessor or peripheral computer is capable of comparing the pupil""s response data to the database of normal measurements and providing conclusions as to whether the pupil""s response data falls outside of the norm and indicates Glaucoma.
In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer for detecting elevated intracranial pressure, and for methods of implementing and utilizing such a diagnostics system. This system comprises a pupilometer for generating a light source and projecting it to the eye and obtaining data descriptive of one or more pupilary characteristics. The system can further comprise a database for storing data descriptive of one or more pupilary characteristics, and a central processing unit, which may be coupled to the pupilometer, for comparing the data obtained by the pupilometer to the data stored within the database such that the comparison will reveal whether the occulomotor nerve (CNIII) is compromised, thus indicating elevated intracranial pressure.
An exemplary embodiment of the invention is illustrated by a method of detecting elevated intracranial pressure. The method comprises the steps of: providing a pupilometer, wherein the pupilometer comprises a light source that is amplitude modulated; continuously projecting light generated by the light source for a given length of time onto the eye of a patient in a predetermined pattern of amplitude modulation; obtaining, using the pupilometer, a first set of data representative of the pupil""s response to the modulated light; storing within a database a second set of data representing pupilary response to light stimulus received in said predetermined pattern of amplitude modulation; and comparing within a data analysis system said first set of data with said second set of data in order to determine whether the occulomoter nerves are compromised, thus indicating intracranial pressure.
In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer for assessing the level of brain function, and for methods of implementing and utilizing such a diagnostics system. This aspect of the invention provides a system comprising a pupilometer for obtaining data descriptive of one or more pupilary characteristics from a subject. The pupilometer may comprise means for providing a visual field to the subject such as a light generated from a visual light source. The system further comprises a database for storing data descriptive of a plurality of pupilary characteristics associated with a set pattern of visual field movement, and a central processing unit coupled to the pupilometer and the database for comparing the data obtained by the pupilometer to the data stored within the database to assess the subject""s level of brain function.
In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer for testing the functional integrity of afferent peripheral and cranial pathways as well as testing efferent cranial nerve involvement in patients with afferent pupilary defects, and for methods of implementing and utilizing such a diagnostics system. This system and associated method comprise a pupilometer as previously described, for obtaining data descriptive of a plurality of pupilary characteristics from an eye of a patient. The system further comprises a database for storing data descriptive of a plurality of pupilary characteristics, and a central processing unit coupled to the pupilometer for comparing the data obtained by the pupilometer to the data stored within the database such that neurological disease or trauma may be diagnosed based upon that comparison. The pupilary characteristics being compared may be the amplitude of the pupilary response to a noxious stimulus or the velocity of pupilary response to a noxious stimulus. The method associated with this aspect of the invention comprises the steps of providing a pupilometer, and obtaining, using the pupilometer, pupilary response data from the eye of a patient. The pupilary response data can represent one or more pupilary response characteristics of the eye being tested. The method can further comprise the steps of storing within a database data representative of a plurality of pupilary response characteristics, and comparing with a data analysis system the pupilary response data obtained from the patient with the stored data to determine whether neurological disease or trauma is indicated.
In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer for testing the functional integrity of auditory pathways, and for methods of implementing and utilizing such a system. The system comprises a pupilometer for obtaining data descriptive of one or more pupilary characteristics of an eye of a patient, as described herein. The system further comprises a sound generating transducer in connection with an ear-piece, wherein the transducer is synchronized to the pupilometer such that images of the eye are captured by the pupilometer in sequence with the generation of sound. Thus, hearing can be tested in a quantifiable and objective manner by analyzing pupilary response rather than relying on the patient to consciously respond to the stimulus.
A method for testing the functional integrity of auditory pathways comprises the steps of providing a pupilometer as described herein, providing a sound generating transducer in connection with an ear-piece, and obtaining, using the pupilometer, a first set of data descriptive of one or more pupilary characteristics from an eye of a patient or subject. The method may further comprise the steps of storing within a database a second set of data descriptive of a plurality of one or more pupilary characteristics associated with pupilary response to sound, and comparing within a data analysis system the first and the second sets of data to determine whether the subject""s hearing is impaired.